Suction operated yarn end clamping means for circular knitting machines



Feb. 10, 1970 M. B.BAKER ET AL 3,494,151

' I SUCTION OPERATED YARN END CLAMPING MEANS FOR CIRCULAR KNI NG MACHINES I Filed Jan. 1968 H Q m INVENTORSI MARVIN B. BAKER and JAMES T. MARLOW ATTORNEYs United States Patent 3,494,151 SUCTION OPERATED YARN END CLAMP- ING MEANS FOR CIRCULAR KNITTING MACHINES Marvin B. Baker and James T. Marlow, Blue Ridge, Ga., assignors to Van Raalte Company, Inc., New York, N.Y., a corporation of New York Filed Jan. 22, 1968, Ser. No. 699,434 Int. Cl. D04b 9/06 US. Cl. 66-140 4 Claims ABSTRACT OF THE DISCLOSURE Suction-operated yarn control means is provided for positively holding yarn ends in a textile machine, such as a circular knitting machine, wherein yarns are selectively withdrawn from corresponding yarn supply packages. The yarn end control means includes a fixed clamping element having an upstanding annular portion, and a suction-operated movable yarn clamping element having a depending annular portion adapted to surround and mate with the upstanding annular portion of the fixed clamping element so that yarns clamped therebetween will not be released until the movable yarn clamping element is raised.

The present invention relates generally to yarn end control means for textile machines and more particularly to a yarn end control device for circular hosiery knitting machines.

Most circular knitting machines currently producing ladies hosiery are provided with a yarn cutter positioned inside of and closely adjacent the circle of needles so that during yarn changes the yarns are cut closely adjacent the needle circle. By closely cutting the leading ends of the yarns introduced and the trailing ends of the yarns withdrawn from the knitting position, the necessity of trimming long loose yarn ends in a subsequent operation is eliminated. These hosiery knitting machines are also provided with some type of yarn end control means which is located between the yarn feed fingers and the yarn cutting means and which operates to retain the end portions of the inactive yarn in proper position to be subsequently fed to the needles and to remove the free terminal end portions formed when the yarn is initially introduced to the needles and the leading end is cut closely adjacent the needles.

Most knitting machines of this type are provided with yarn end control means which includes a mechanical clamp for holding the yarns and a suction tube into which the ends of the yarns are drawn during yarn changes. This arrangement requires accurate operational timing of the suction and clamp. The need for separate clamp and suction controls is eliminated by the suction-operated clamping device disclosed in the Wilson Patent No. 3,228,213. The device of this patent includes a suctionoperated ball which takes the place of the separate yarn clamp; however, this ball does not provide a positive clamp for the yarn because the clamping action depends upon the weight of the ball resting on the yarn, Where yarns of different denier or size pass beneath the ball, the yarns of smaller size will not be engaged and held thereby and stretchable yarns or covered elastic yarns will not be positively held by this ball type clamp.

With the foregoing in mind, it is an object of the present invention to provide yarn end control means which overcomes the above-noted and other objections and provides a positive clamping of various sizes and types of yarns during those periods when the yarns are not being fed to the textile machine.

It is a further object of this invention to provide yarn end control means which is simple in construction, provides long and trouble-free operation, and may be easily installed upon conventional textile machines, such as circular hosiery knitting machines, Without requiring extensive modification thereof.

More specifically, the yarn end control means of this invention comprises a yarn inlet nozzle having an upstanding annular fixed clamping portion, and a vertically movable clamping member having a depending annular clamping portion on the lower end thereof. The diameter of the depending annular clamping portion is suificient that it surrounds and engages the upstanding annular clamping portion when the movable clamping member is in a lowermost position to clamp yarns therebetween. Suction means is provided to raise the movable clamping member and to thereby free the clamped yarns and to draw any free yarn ends into the inlet nozzle and past the movable clamping member.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which FIGURE 1 is a fragmentary top plan view of the dial of a circular two-feed knitting machine and illustrating the yarn feed fingers at each of the two yarn feeding stations, with the yarn end control means of the present invention located between the feed fingers of each station and the corresponding yarn cutters;

FIGURE 2 is an enlarged fragmentary elevational view of one yarn end control device, being taken substantially along the line 22 in FIGURE 1;

FIGURE 3 is an enlarged vertical sectional View through the yarn end control device, being taken substantially along the line 3-3 in FIGURE 2; and

FIGURE 4 is an enlarged horizontal sectional view taken substantially along the line 4-4 in FIGURE 3.

Generally, the yarn end control means of the present invention includes a tubular housing 10 (FIGURE 3), a vertically movable clamping element in the form of a cylindrical piston 11 supported for vertical movement in the tubular housing 10, a yarn inlet nozzle 12 forming a fixed yarn clamping element and adapted to be matingly engaged by the lower portion of the piston 11 to positively clamp yarns therebetween when the piston is in a lowermost position. When sufiicient suction is created in the upper end of the tubular housing 10, the piston 11 is raised from mating engagement with the nozzle 12 and releases the clamping engagement of the yarns so that the yarn ends are drawn up into the yarn end control means.

The present yarn end control means is shown associated with a two-feed circular hosiery knitting machine of the type illustrated in US. Patent No. 3,097,512. This type of machine includes a main yarn feed station 15 having individual yarn feed fingers 16 that are movable into and out of yarn feeding position relative to a circle of needles N. The yarn feed fingers 16 are moved into and out of operative position in accordance with a predetermined pattern to feed yarns Y to the needles, in a well known manner. The machine is also provided with an auxiliary feeding station 17 having individual yarn feed fingers 18, operable to selectively feed yarns Y to the needles N.

A dial plate 20 is supported in the usual manner Within the circle of needles N and a yarn cutter disc 22 is supported beneath the dial plate 20 and rotates in a counterclockwise direction with the needles N. The cutter disc 22 is provided with saw-tooth type teeth which extend outwardly beyond the dial plate 20 and cooperate with cutter blades 23, 24 to sever yarns closely adjacent the knit fabric, in a manner to be presently described. The cutter blades 23, 24 are supported on respective pivot 3 arms 25, 26 which are at times raised by corresponding control links 27, 28 to move the cutter blades 23, 24 out of engagement with the cutting disc 22. The usual transfer point bed is supported beneath the dial plate 22 and supports the usual transfer bits, not shown, for radial movement in a conventional manner.

Rotation is imparted to the cutter disc 22 and the dial bed by means of a drive shaft 30 which extends downwardly through the central portion of the dial plate 20 and through a support sleeve 31 and on which the upstanding hub portion 32 of the dial plate 20 is supported. The drive shaft 30 is connected by conventional means to the drive of the machine so that the cutter disc 22 is rotated in timed relationship to rotation of the needles N. The upper level of the dial plate 20 is supported at the proper level so that yarns from the feed fingers at the stations 15, 17 pass across the upper surface thereof as they are guided to the cutter blades 23, 24 by the cutter disc 22.

In the present instance, a yarn end control device is provided in advance of each cutter blade 23, 24; however, in some two-feed knitting machines all yarn ends are cut at one location and in this case, it would be necessary to provide only a single yarn end control device. Of course, a single yarn end control device would be provided on a single-feed machine and more than two yarn and control devices may be provided on knitting machines having more than two feeds. The yarn end control device posi tioned between the fingers 18 at the auxiliary feed station 17 and the cutter blade 24 will be described in detail and the corresponding parts of the other yarn end control device will bear like reference characters with the prime notation added.

The upper end of the tubular housing is communicatively connected with suction means including a cap member 35 (FIGURES 2 and 3) which is suitably connected to the upper end of the tubular housing 10, as by set screws 36, and has a reduced upper portion connected to the lower end of a suction line 37. The upper curved end of the suction line 37 (FIGURE 1) has one end of an air pressure line 40 suitably connected thereto and the other end of which is connected to a suitable air pressure source and by means of a patterned-operated valve, not shown, which operates during yarn changes to allow air under pressure to pass through the line 40, the upper end of the tube 37 and into a yarn end collection chamber 41. The air may escape from the collection chamber 41 through a screen 42 and a removable deflector cover 43 is provided for removing the accumulated yarn ends therefrom. As air under pressure passes through the line 40 and into the upper portion of the suction tube 37, reduced pressure or suction is created in the lower portion of the tube 37 and in the tubular housing 10.

The yarn inlet nozzle 12 has a lower peripheral shoulder which is suitably secured, as by a press fit, inside of the lower end of the tubular housing 10, and an upper peripheral shoulder which forms an annular upstanding fixed yarn clamping portion 45. An annular space 46 is provided between the outer periphery of the upstanding fixed yarn clamping portion 45 and the adjacent inner surface of the tubular housing 10. A yarn entrance bore 47 extends upwardly through the center of the inlet nozzle 12 and the upper and lower ends of which are preferably beveled outwardly as at 48, 49. The lower level 48 provides a smooth entrance for the yarn Y and the upper bevel 49 provides a relatively sharp edge, over which the yarn passes when clamped, in a manner to be presently described.

A support bracket 10a is suitably secured at one end to the tubular housing 10 and its other end is fixed on the upstanding hub 32 of the dial plate 20, as by a screw 10b (FIGURES l and 2). The bracket 10a supports the lower surface of the inlet nozzle 12 in spaced relationship above the upper surface of the dial plate (FIGURE 2) so that yarns may pass therebeneath.

The movable clampin member 11 has a bore 50 extending upwardly from its lower portion, the inner sur face of which tapers upwardly so that the diameter at the lower extremity is larger than the annular upstanding fixed yarn clamping portion 45 and the outer peripheral surface at the lower end of the member 11 is tapered inwardly so that the lower edge forms a fairly sharp downwardly extending annular movable yarn clamping portion 52. The movable clamping portion 52 surrounds the annular upstanding fixed yarn clamping portion 45 of the nozzle 12 and moves into the annular space 46 when the member 11 moves to the lower position shown in FIGURE 3 to thereby clamp the yarn. Only a single yarn Y is shown in FIGURES 3 and 4; however, there are usually several yarns drawn into the control device and held thereby. As best shown in FIGURE 3, the clamped yarn is positively held between the movable clamping portion 52 and the fixed clamping portion 45 and assumes an S-shaped configuration as it passes up over the fairly sharp upper edge of the inlet nozzle 12 and then downwardly beneath the fairly sharp lower edge of the suction-operated clamping member 11. Thus, the clamped yarn changes directions and may be said to be bent back upon itself as it is held between the clamping members.

There is suflicient clearance between the member 11 and the housing 10 for yarn to pass and the upper end of the member 11 is provided with diametrically opposed pairs of grooves 54 which are preferably rounded in the lower ends thereof and taper inwardly toward the upper end of the member 11. These grooves 54 provide passageways for air and yarns when the member 11 is drawn upwardly by the suction and its upper end engages the cap member 35, which provides stop means limiting the upward movement of the member 11.

Assuming that the needles N are rotating in the normal counterclockwise direction in FIGURE 1, and the yarns are being fed to the needles form the No. 1 yarn fingers at the main feed station 15 and the auxiliary feed station 17, the yarns Y and Y from the remaining feed fingers will be held by the respective yarn end control devices of the present invention, no air pressure being passed through the lines 40, 40. There are usually several points during the knitting of a ladies stocking where it is desirable to change the yarn being knit. For example, in support stockings, a covered spandex type yarn is usually inserted in the circularly knit portions of the leg and foot and removed during the knitting of the toe and heel pockets and during the knitting of the welt. Also, in ladies seamless sheer stockings, it is the usual practice to knit the welt of a heavier yarn than the sheer leg portion. In many cases a heavier reinforcing yarn is knit in the heel and toe.

It is the usual practice to move an inactive yarn feed finger into feeding position before removing the yarn which is to be discontinued so that both yarns are knit in plated relationship on a few needles to thereby tie the outgoing end of yarn to be removed and the ingoing end of the new yarn securely into the knit fabric. Just prior to the yarn change, air pressure is introduced through the lines 40, 40" to create suction in the upper ends of the yarn end control devices. The suction in the upper end of the housing 10 (FIGURE 3) is sufiicient to lift the movable yarn clamp member 11 out of clamping engagement with the yarn inlet nozzle 12 and holds the free ends of the released yarns under tension while the introduced yarn is picked up and knit by the needles.

The first needle to knit draws the yarn down into engagement with the teeth on the disc 22 so that it is brought around by the disc 22 to the cutter 24. The suction in the tubular housing 10 maintains tension on the yarn as the distance from the first needle decreases and then increases until the yarn is cut by the cutter 24 to form a free terminal end portion which is then immediately drawn up through the tubular housing and deposited into the collection chamber 41. The active yarn is withdrawn by raising the yarn feed finger after it has knit With the yarn being introduced for a few needles and the last needle to knit and the disc 22 carry the yarn around to cutter 24 so that the yarn extends from the raised yarn feed finger and above the upper surface of the dial plate 20. To insure that the withdrawn yarn passes beneath the lower end of the inlet nozzle 12, it is preferred that some type of guide be provided. As shown in FIGURE 1, guide wires 56, 56 are secured at one end to the dial plate 20 and their free ends are curved upwardly so that the yarns are directed therebeneath.

As the withdrawn yarn is brought to the cutter 24 by the disc 22 and cut closely adjacent the needles, the suction in the tubular housing 20 draws that free end portion of the yarn extending from the cutter 24 up into the tubular housing 10 and beside the movable clamping member 11. When the yarn change is completed, the air pressure through the line 40 is cut off to stop the suction in the tubular housing 10 and the movable clamping member 11 moves downwardly by gravity into seating engagement with the yarn inlet nozzle 12, as shown in FIGURE 3, thereby clamping any yarn ends extending into and through the air inlet nozzle 12. As the annular depending movable clamping portion 52 moves down around and engages the annular upstanding fixed clamping portion 45, the yarn assumes a substantially S-shaped configuration as it is firmly clamped therebetween so that it may not pull out. Thus, the clamping or holding action of the present device is not dependent solely on the Weight of the movable clamping member 11, since the yarn is snubbed as it is held in the S-shaped configuration.

The yarn end control means of the present invention thus includes a suction-operated clamping device which provides a positive grip on the yarn and prevents slippage. The clamping device operates automatically in response to the suction and the suction may be controlled to actuate the yarn clamp at the desired time, relative to a yarn change on the knitting machine.

In the drawings and specifications there has been set forth a preferred embodiment of the invention and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

We claim:

1. In a circular knitting machine having a circular series of needles, a dial plate supported within the circle of needles, a yarn feeding station adapted to selectively feed yarns to the needles, and yarn cutting means spaced from said yarn feeding station, the levels of said dial and said yarn feeding station being such that yarns pass across a portion of the upper surface of said dial during yarn changes, the combination therewith of improved yarn end control means supported between said yarn feeding station and said yarn cutting means and comprising 1) a tubular housing supported above said dial and having upper and lower ends, said upper end having a yarn exit therein, and said lower end being supported in spaced relationship above said dial,

(2) suction means communicatively connected with the upper end of said tubular housing and being operable during yarn changes,

(3) a yarn inlet nozzle secured in the lower end of said tubular housing, said inlet nozzle including an upstanding annular fixed yarn clamping portion extending upwardly into and spaced inwardly from the inner periphery of said tubular housing and defining an annular space therebetween, said inlet nozzle having a yarn entrance bore extending upwardly through the center thereof, and

(4) a movable yarn clamping member supported for vertical movement in said tubular housing and above said inlet nozzle, said movable yarn clamping member including 21 depending annular yam clamping portion on the lower end thereof, the inner surface of said depending annular yarn clamping portion being engageable with the outer surface of said upstanding annular yarn clamping portion when said movable yarn clamping member is in a lowermost position to clampingly engage any yarns passing therebetween, whereby the yarns pass over said upstanding annular yarn clamping portion, beneath said depending annular yarn clamping portion, and upwardly toward said yarn exit in the upper end of said tubular housing so that the clamped yarn assumes as substantially S-shaped configuration, said movable yarn clamping member having an upwardly elongated portion above said depending annular yarn clamping portion and providing sufficient weight to maintain the S-shaped configuration in the clamped yarn, said suction means being operable to raise said movable clamping member in the tubular housing and to release yarns clamped thereby while drawing the free ends of any adjacent yarns into said inlet nozzle.

2. In an apparatus according to claim 1 wherein said movable yarn clamping member is cylindrical and said depending annular yarn clamping portion is formed by a bore extending upwardly from the lower end of said cylindrical clamping member, the diameter of said bore gradually decreasing in an upward direction and the diameter of the lower extremity of said bore being slightly larger than the outer diameter of the upper portion of said upstanding annular yarn clamping portion of said yarn inlet nozzle.

3. In an apparatus according to claim 2 wherein a cap member is secured on the upper end of said tubular housing and has a reduced central opening communicatively connected to said suction means, said cap member forming stop means limiting the upward movement of said movable yarn clamping member, the upper end of said cylindrical yarn clamping member including opposing grooves tapering inwardly toward the upper end thereof and providing passageways for air and yarn carried thereby.

4. In an apparatus according to claim 1 wherein the upper and lower ends of said yarn entrance bore of said yarn inlet nozzle are beveled outwardly, the lower bevel providing a smooth entrance for yarns, and the upper bevel providing a relatively sharp upper terminal edge on said upstanding annular yarn clamping portion over which the clamped yarn extends.

References Cited UNITED STATES PATENTS 2,718,363 9/1955 Roberts 242149 2,736,511 2/ 1956 Roberts 242-149 3,228,213 1/1966 Wilson.

FOREIGN PATENTS 563,593 11/1932 Germany.

ROBERT R. MACKEY, Primary Examiner 33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 1 D d February 10 Inventor) Marvin B. Baker and James T. Marlow It is certified that error appears in the above-identified patent and that said Letfers Patent -arehereby corrected as shown below:

r- CoIumn 3, line 26, "and" (seconcl 'oocurr eri ce) should be end Column 3, line 43, "patterned-, should be pattern- Column 3, line 64, "level" should be bevel v--.- Column 4, line 38, "form" should be from Column 5, line 44, j'specifications" should be specification Column 6, line 21', "as" should be a (SEAL) mm m E a-I mung m 7 Commissioner of Patents 

